The use of laminated plastic data cards has increased rapidly in recent years. Large corporations, schools, governmental bodies, and other organizations regularly issue millions of cards annually. Unfortunately, the cost of equipment used in mass production of data cards is often prohibitive for an organization which needs to make only a few cards daily or which makes a moderate number of cards on only a few occasions each year. This has led to various medthods to produce plastic laminated data cards on a small scale basis, using only a minimum of equipment.
Some of these methods have merely called for inserting a data sheet between two sheets of plastic laminating material which are then subjected to heat and pressure to produce a laminate that is subsequently cut to a final desired shape. However, the cutting is time consuming, often inaccurate, and rather wasteful of the plastic laminating material.
Another method uses a pre-cut blank, formed from a single sheet of plastic material. The blank includes first and second panels, one of which is folded over on the other to form a so-called butterfly pouch. A document to be sealed is placed between the panels of the pouch, which are then laminated together under heat and pressure. To ensure that the blank is folded accurately, a fold line is cut into the plastic sheet at the juncture of the first and second panels.
One prevalent problem in cutting the fold line of a butterfly pouch is obtaining the proper depth of cut. Obviously, the fold line must be deep enough to sufficiently weaken the blank to ensure accurate folding. However, the fold line must not be cut so deeply as to cause the blank to separate when subsequently folded. The blanks are typically die-cut from a large sheet of plastic material. Since the sheet material is usually only a few mils in thickness, it can be seen that the depth of the score line must be quite accurately controlled. However, given the unavoidable tolerances in a commercial scale manufacturing operation, variations in the depth of cut cannot be economically avoided. Variations in the material thickness, the accuracy of the die cutting machine, and wear of the die's cutting edges all lead to variations in the depth of cut. Given the small thickness of the plastic material, even a minor variation in the cut can be a large percentage of the desired depth. The problem has been regarded as one of accommodating these variations during the production of a commercial number of blanks.
A similar problem exists in connection with computer print-out sheets intended to be retained on a permanent or semi-permanent basis. If a print-out is to be retained for long-term use, a plastic sheet is greatly preferable to paper as the base for the print-out. But a fan-fold arrangement, permitting folding of the print-out into a compact series of panels in parallel facing relation, tends to separate along the fold lines if the base is sheet plastic instead of paper. As in the case of the butterfly pouch, it is quite difficult to cut the fold lines deep enough to allow easy folding without incurring the possibility of panel separation along the fold lines. Indeed, the repeated folding and unfolding often encountered in use of a fan-fold product exacerbates the problem.